Hemodialysis systems have been designed to carry out blood therapy procedures such as slow continuous ultrafiltration (SCUF), continuous veno-venous hemofiltration (CVVH), continuous veno-venous hemodialysis (CVVHD) or continuous veno-venous hemodiafiltration (CVVHDF). These therapies, referred to as CRRT, are designed for removal of metabolic waste and excess fluid from patients in fluid overload and who need renal support. Presently available extracorporeal blood treatment apparatus often requires inconvenient and time consuming setup procedures including cleaning and/or replacing the blood and/or fluid tubing for different patients and for different therapies. Such procedures may require the apparatus to be removed from a patient's bedside or room to another location, or replacing an apparatus with a system that is set up and configured for carrying out a specific therapy.
U.S. Pat. No. 5,910,252 describes an apparatus configured for performing the different blood therapies and provides means for selecting one of the therapies to be carried out. The described apparatus is an assembly of all pumps, tubing, multiple fluid supply reservoirs, waste fluid container and filter cartridge necessary for performing any one of the selected blood therapies.
U.S. Pat. No. 6,200,485 describes another multipurpose hemofiltration system comprising an assembly of a blood filter cartridge, pumps, fluid reservoir and waste fluid container, components for comparing the weights of the fluid reservoir and waste fluid container and means for controlling the pump operations and rate in response to the compared weights during the therapy.
A Prismaflex™ system marketed by Gambro of Lakewood, Colo. offers selection of different CRRT therapies. The system allows the user to select a prepackaged, preassembled assembly incorporating all of the components including specific column and type of filter membrane or membrane filter surface area and all preconnected tubing for carrying out the selected therapy.